Oweidat Majd, Abu Rumilah Anas
College of Medicine, Hebron University, Hebron, West Bank, Palestine.
Division of Endocrinology, Department of Internal Medicine, Al-Ahli Hospital, Hebron, West Bank, Palestine.
AACE Endocrinol Diabetes. 2025 Apr 10;12(1):19-23. doi: 10.1016/j.aed.2025.03.003. eCollection 2025 May-Jun.
BACKGROUND/OBJECTIVE: Cushing syndrome (CS) is a life-threatening condition that occurs due to hypercortisolism. The most common cause of endogenous CS is adrenocorticotropic hormone (ACTH)-dependent CS caused by a pituitary adenoma (Cushing disease). Ectopic production of ACTH from tumors elsewhere in the body is rare and is most often associated with small cell lung cancer. This report describes a patient with ACTH-dependent CS secondary to metastatic medullary thyroid cancer (MTC), a rare cause of ectopic CS.
A 52-year-old man presented with progressive diarrhea, fatigue, muscle weakness, and hypokalemia. Initial investigations revealed metabolic alkalosis, elevated urinary potassium excretion, and fasting hyperglycemia. Evaluations confirmed ACTH-dependent hypercortisolism with elevated serum ACTH and urinary free cortisol levels. Imaging and fine needle aspiration confirmed MTC with metastatic lymph node involvement, supported by elevated serum calcitonin and carcinoembryonic antigen levels. Surgical intervention revealed extensive tumor invasion but was complicated by vascular injuries, resulting in postoperative hypoxic brain injury and fatality.
This case highlights the importance of early recognition and investigation of unexplained ACTH-dependent hypercortisolism. Delayed diagnosis complicates management, increases morbidity, and worsens outcomes. A systematic diagnostic approach-including biochemical markers, imaging, and cytology-is crucial in identifying rare causes of hypercortisolism.
Early evaluation of persistent hypokalemia and hypercortisolism is essential to prevent delayed diagnosis of CS. This case highlights MTC as a rare source of ectopic ACTH secretion.
背景/目的：库欣综合征（CS）是一种因皮质醇增多症而危及生命的疾病。内源性CS最常见的病因是垂体腺瘤导致的促肾上腺皮质激素（ACTH）依赖性CS（库欣病）。身体其他部位肿瘤异位分泌ACTH的情况罕见，且最常与小细胞肺癌相关。本报告描述了一例继发于转移性甲状腺髓样癌（MTC）的ACTH依赖性CS患者，这是异位CS的一种罕见病因。
一名52岁男性出现进行性腹泻、疲劳、肌肉无力和低钾血症。初步检查发现代谢性碱中毒、尿钾排泄增加和空腹血糖升高。评估证实为ACTH依赖性皮质醇增多症，血清ACTH和尿游离皮质醇水平升高。影像学检查和细针穿刺确诊为MTC伴转移性淋巴结受累，血清降钙素和癌胚抗原水平升高支持这一诊断。手术干预发现肿瘤广泛侵犯，但因血管损伤而出现并发症，导致术后缺氧性脑损伤和死亡。
本病例强调了早期识别和调查不明原因的ACTH依赖性皮质醇增多症的重要性。延迟诊断会使治疗复杂化，增加发病率，并使预后恶化。包括生化标志物、影像学和细胞学在内的系统诊断方法对于识别皮质醇增多症的罕见病因至关重要。
对持续性低钾血症和皮质醇增多症进行早期评估对于预防CS的延迟诊断至关重要。本病例突出了MTC作为异位ACTH分泌的罕见来源。
